Standard flexible body armors (a.k.a. “bullet proof” vests) are commonly used by police officers throughout the United States. However, these vests are incapable of defeating the ballistic threats imposed by military pattern rifles firing high-velocity, armor-piercing (AP) projectiles. As these threats are frequently encountered during wartime, the US military has adopted body armor with pockets which can accommodate hard ballistic trauma plate inserts, which can defeat AP rifle fire. The National Institute of Justice (NIJ) classifies AP rifle fire as threat level IV, and any ballistic armor plate certified to defeat a level IV threat must be capable of stopping projectiles up to and including AP 7.62×63 mm (30-06). Current state of the art level IV trauma plates are manufactured from laminate metal ceramic composites, and usually measure a minimum of 0.7″ thick. A typical level IV plate measuring 10″×12″×0.7″ weighs about 8 pounds and has a relatively high cost (e.g., about $300). Similarly constructed ceramic composites are also used for armor military vehicles.
Current ceramic composite armor plating has several issues that should be ameliorated:
(1) Weight: Soldiers are often overburdened by the additional weight of these plates, and are forced to forgo the additional protection in order to carry other gear. Additionally, the weight reduces the maximum size of the plates a soldier can carry and leaves unprotected areas on a soldier's body.
(2) Bulk: The bulkiness of the plate inserts makes them visible to the enemy, allowing enemy soldiers to shoot around the plates hitting more vulnerable areas.
(3) Overheating: The heat trapping properties of trauma plates make them uncomfortable to wear in hot, desert climates. Therefore, the existence of a lightweight, lower profile, breathable Level IV trauma plate would be of great interest to the US armed forces.
(4) Thermal attack: Ceramic armor plates are not designed to defend against thermal or directed energy attacks. The two (2)-dimensional nature of the current laminated construction provides poor thermal conductivity, allowing hot spots to develop in the event of a thermal attack.
(5) Damage resistance: Once an armor plate is hit it usually breaks in pieces and does not continue to defend against impacts.
US Patent Publication No. 20060234577, which is incorporated by reference herein in its entirety, describes a type of body armor constructed from a fabric impregnated with a shear thickening fluid. An advantage of the armor described in this patent application is that it remains flexible until struck, but this armor is not designed to compete with currently available hard armor plate inserts (so called level III or higher trauma plates) but rather to replace current flexible body armors. As such, this patent application does not provide for non-flexible armors (suitable for trauma plates).
US Patent Publication No. 20060225180, which is incorporated by reference herein in its entirety, describes a type of reactive armor utilizing gas pressure to actively repel incoming threats, unlike the non-flexible armors described above which are of the passive type.
US Patent Publication Nos. 200060137517 and 20060105184 and U.S. Pat. No. 7,069,836, which are incorporated by reference herein in their entirety, describe a type of metal/ceramic armor which is constructed with metallic plates and ceramic fillers. However, these patent disclosures do not provide for an ordered, three (3)-dimensional component as discussed in more detail below.
US Patent Publication Nos. 20050072294 and 20020012768 and U.S. Pat. Nos. 7,117,780, 6,575,075, 6,480,734, 6,289,781, 6,112,635, 5,763,813, 5,361,678, which are incorporated by reference herein in their entirety, describe a type of ceramic armor wherein close packed pellets of a hard ceramic phase are surrounded with an elastic (tough) material. While the pellets are closely packed together and form a regular, 3-dimensional repeating pattern, they do not provide for a continuous truss like structure.
U.S. Pat. No. 6,955,112, which is incorporated by reference herein in its entirety, describes a type of composite armor based on a ceramic fibrous or foam-like structure infused with liquid metal. However, this patent does not provide for using an ordered framework.
U.S. Pat. Nos. 6,609,452, 5,372,978, and 4,604,249, which are incorporated by reference herein in their entirety, describe the manufacture of ballistic armor plates composed of a porous SiC infiltrated with various metals (e.g. steel). None of these patents provide for the concept of utilizing SiC in an organized, framework or other similar type structure.
U.S. Pat. No. 5,654,518, which is incorporated by reference herein in its entirety, describes the construction of a “double truss structural armor”. This armor is constructed by laminating corrugated ceramic and metallic layers. As such, the structure disclosed in this patent disclosure is not a continuous 3-dimensional structure.
U.S. Pat. Nos. 5,306,557, 5,114,772, 4,876,941, 4,309,487, 3,977,294, which are incorporated by reference herein in their entirety, describe the construction of hard armor plates composed of laminated/multilayered ceramics, metals, polymers and/or carbon fiber sheets. However, these structures are not 3-dimensional structures.
U.S. Pat. No. 4,030,427, which is incorporated by reference herein in its entirety, describes a type of armor plate formed by dispersing titanium carbide (ceramic) particles throughout a tough titanium-nickel alloy. Because the ceramic particles are randomly distributed throughout the metallic matrix, there is no ordered 3-dimensional component to the structure disclosed in this patent.
U.S. Pat. No. 5,221,807, which is incorporated by reference herein in its entirety, describes a type of ballistic armor utilizing perforated/porous ceramic layers sandwiched in a laminated plate like structure. Again, the structure disclosed in this patent is not a 3-dimensional continuous structure.
In view of the foregoing, the above described patent disclosures describe various concepts for creating armor plate through a ceramic/metallic composite structure, but these disclosures do not provide a concept for fabricating armor from small scale 3-dimensionally ordered truss structure. That is, these patent disclosures provide ceramic phase that is either distributed as a powder, organized by virtue of stacking ceramic balls/pellets, or laminated as alternating ceramic and metallic plates. As such, there is a need for an armor that incorporates ceramic and metallic continuous phases, interwoven and repeating with both long range and short range order.